<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title>3.关于函数的返回值</title>
	</head>
	<body>
		<script type="text/javascript" >
			function demo(){
				return setTimeout(()=>{
					return 999
				},1000)
			}	
			const x = demo()
			console.log(x)
		</script>
	</body>
</html>